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Penguins of South
America and the Falkland Islands

by Mike Bingham.
Published 1998 in PENGUIN CONSERVATION 11(1): 8-15.

INTRODUCTION
TO THE REGION

World-wide there
are 17 species of penguin, of which 7 regularly breed around South
America and the Falkland Islands. Three of these species are of
the Genus Spheniscus, and are found nowhere else in the world. These
are the Magellanic Penguin (Spheniscus magellanicus) common
around southern South America and the Falkland Islands, the Humboldt
Penguin (Spheniscus humboldti) restricted to the Pacific
coast of Chile and Peru, and the Galapagos Penguin (Spheniscus
mendiculus) found only at the Galapagos Islands off the coast
of Equador.

The King Penguin
(Aptenodytes patagonicus) has a limited presence in the region,
with a breeding population of around 400 pairs in the Falkland Islands
(Bingham 1996). King Penguins have not bred in South America since
the colony on Islas de los Estados was wiped out by sealers during
the last century. The Falkland Islands hold around 20% of the world
population of Gentoo Penguin (Pygoscelis papua), with a total
population of 65,000 breeding pairs at 81 sites (Bingham 1996).

The Falkland Islands
and South America are home to two species of the Genus Eudyptes;
the Southern Rockhopper (Eudyptes chrysocome chrysocome)
and the Macaroni (Eudyptes chrysolophus). The Southern Rockhopper
is a subspecies that is restricted to the Falkland Islands and South
America, with the Falkland Islands holding a breeding population
of about 300,000 pairs at 36 sites (Bingham 1996). The Falkland
Islands population of Macaroni Penguins is very small, with no individual
colonies and only individual pairs found breeding amongst Rockhoppers
colonies. The total Falklands population stands at no more than
about 50 pairs.

THE CENSUS

By comparison to
other areas of research, conducting counts of breeding populations
can seem fairly mundane. Nevertheless the value of data obtained
from population censuses should never be underestimated. It is only
by recording population size and distribution that we are able to
determine with any accuracy whether a population is thriving or
declining, or how a population has been affected by disasters such
as an oil spill or El Niño.

During 1995/96,
a population census of all penguin species (except the Magellanic
Penguin) was conducted around the Falkland Islands (Bingham 1996).
Every breeding colony was visited, and population totals for each
species obtained. Comparing this data with previous studies revealed
that the Southern Rockhopper population had crashed to a fraction
of its former size (Bennett 1933, Bingham 1994c Bingham 1995a, Bingham
1996). With no obvious reason for this dramatic decline, apart from
speculation about commercial fishing, it became a priority to census
the remainder of the world population located in South America,
to determine how wide-spread the decline had been.

It had been shown
during the 1995/96 census of the Falkland Islands, that it requires
little extra effort to census all penguin species during the course
of such a census. The only exception to this was the Magellanic
Penguin, which because of its widespread, low-density distribution
in burrows, made it impossible to census with methods employed for
surface nesting species. For this reason the Magellanic Penguin
had been excluded from the Falkland Islands census.

On that basis it
was decided that a census would be conducted of all South American
penguins during the 1996/97 breeding season, except for those of
the Genus Spheniscus. In theory this meant that all species covered
by the Falkland Islands census would be included, although King
and Gentoo Penguins were not expected to be encountered during the
South American census.

During the 1995/96
Falkland Islands census it had been possible to conduct ground counts
of incubating pairs at each of the breeding colonies, because most
colonies were relatively accessible (Bingham 1996). By contrast,
many of the South American colonies are remote and inaccessible,
and any attempt to conduct ground counts of each and every colony
would have been doomed to failure. It was therefore decided from
the outset that the census would be conducted by light aircraft,
thereby negating the need to get ashore at difficult and remote
sites.

The location of
all the Falkland Islands breeding sites had been known prior to
the commencement of the 1995/96 census (Bingham 1996), but this
was certainly not the case for South America. Although data did
exist for a number of known breeding sites around South America,
it was likely that other sites existed that had not been recorded.
This was another reason for favouring an aerial census, since it
provided the opportunity to cover large areas of suitable coastline
in search of previously unrecorded colonies. This certainly reduced
the margin of error that would otherwise have resulted from new
sites being overlooked, however the margin of error for the actual
counts was clearly greater for aerial counts than for ground counts.

In order to quantify
the margin of error likely to be expected from aerial counts, a
number of aerial censuses were made of Rockhopper colonies in the
Falkland Islands for which the number of breeding pairs was also
determined by ground counts. These aerial counts differed by a maximum
of 14% from ground counts made of the same colony, giving a total
margin of error of +/- 20% for aerial census data (Bingham 1996).

The 1996/97 aerial
census was conducted throughout the known Eudyptes breeding ranges
of Chile and Tierra del Fuego. The Atlantic coast of mainland Argentina
was excluded from the census, since this coastline has been well
studied, and does not hold any breeding sites for species covered
by the census, other than a very small Rockhopper colony on Isla
Pingüino, near Puerto Deseado. This colony is regularly monitored
as part of an ongoing research programme, and population data from
their research was used in favour of duplicating results (Frere
et al. 1993).

CENSUS RESULTS

KING PENGUIN

As expected, no
King Penguins were recorded anywhere in South America.

GENTOO PENGUIN

Somewhat surprisingly,
a very small Gentoo breeding colony was discovered on Islas de los
Estados, containing almost 100 breeding pairs. This was the only
breeding colony of Gentoo Penguin recorded in South America.

SOUTHERN ROCKHOPPER

The 1996/97 census
showed that South America holds a breeding population of about 175,000
pairs of Southern Rockhoppers, at a total of 15 breeding sites.
Apart from the very small colony near Puerto Deseado (Frere et
al. 1993), these breeding sites are restricted to the islands
off Tierra del Fuego and Chile. Combined with the Falkland Islands
population of 300,000 pairs at 36 sites (Bingham 1996), this gives
a world population of 475,000 breeding pairs at 51 sites for the
subspecies Eudyptes c.chrysocome. (South Georgia has been known
to hold a few breeding pairs, but no more than 10 pairs have been
recorded).

MACARONI PENGUIN

The 1996/97 census
showed that South America holds a breeding population of about 12,000
pairs of Macaroni, at a total of 9 sites. These sites are all restricted
to the islands off Tierra del Fuego and Chile. Only the islands
of Diego Ramirez, Ildefonso and Noir hold more than a thousand breeding
pairs.

DISCUSSION

No breeding King
Penguins were observed in South America during the 1996/97 census.
The Falkland Islands population stood at around 400 breeding pairs
during the 1995/96 census (Bingham 1996), and has rapidly expanded
from a population of less than 100 pairs recorded during 1980/81
(Bingham 1995a). With a world population of around 1,500,000 pairs
(Croxall, In press), the Falkland Islands population is of regional
rather than global importance.

A colony of a little
under 100 breeding pairs of Gentoo Penguin was discovered on Islas
de los Estados during the 1996/97 census. The Falkland Islands population
stood at 65,000 breeding pairs during the 1995/96 census (Bingham
1996) out of an estimated world population of 320,000 pairs (Croxall,
In press). The 1995/96 Falkland Islands census indicated a population
decline of around 45% since a similar census conducted during 1932/33
(Bennett 1933).

Annual counts of
selected breeding sites around the Falkland Islands suggested that
much of this decline had occurred during the late 1980s and early
1990s, with low breeding success also being observed during that
period (Bingham 1994a, Bingham 1994d, Bingham 1995a). Continued
monitoring of these sites since then indicates that the Falkland
Islands population has now risen to around 81,000 breeding pairs,
with high breeding success rates having been recorded since 1993/94.
Gentoo populations are known to fluctuate greatly, and it is plausible
that the decline observed previously was merely part of a natural
cycle.

The world population
of Southern Rockhopper Penguins now stands at around 475,000 breeding
pairs, with 63% of the population in the Falkland Islands and 37%
in South America.

Comparison with
previous census data (Bennett 1933) indicates that the Falkland
Islands population has crashed to just 10% of its former size, with
much of this decline having occurred during the 1980s and early
1990s (Bingham 1994c, Bingham 1995a, Bingham 1996). Evidence of
this dramatic decline can also be seen from the breeding sites themselves.
The Falkland Islands breeding sites feature old colonies which have
destroyed the vegetation by years of occupancy, leaving only lichen
covered rocks and stones around the nest-site. The huge breeding
colonies that once produced these areas of barren ground, have now
been reduced to small clusters of birds huddled in the centre of
their stony territories.

The South American
population shows no such evidence of decline, with breeding sites
featuring a healthy mixture of new, middle-aged and old colonies,
indicating a natural cycle of fluctuation and regeneration. Comparison
with previous census data (Venegas 1984, Venegas 1991, Woehler 1993)
also indicates that the South American population had been stable
throughout the 1980s and 1990s, covering the period when over half
the Falkland Islands population had died from starvation. The reason
for such differing fortunes is unknown, although it is interesting
to note that the waters around Tierra del Fuego and Chile are not
heavily fished, whilst those around the Falkland Islands are. In
the Falkland Islands, even internationally recognised sites, such
as Beauchêne Island which is being considered for World Heritage
status, have fleets of fishing boats operating just 3 miles from
breeding Rockhoppers.

The Macaroni populations
of South America (12,000 pairs) and the Falkland Islands (~50 pairs)
must be looked at in the light of a world population of around 9
million breeding pairs (Croxall, In press). These populations are
therefore of regional rather than international importance. There
were no obvious signs of decline amongst the South American population,
and no evidence to suggest that the population has changed greatly
over recent years. The Macaroni is the most numerous of all the
world's penguins.

Although the Magellanic
Penguins were not included in the 1995/96 and 1996/97 censuses,
that is not to say that no work has been done on this species. The
current population along the coast of mainland Argentina is estimated
to be 650,000 breeding pairs (Gandini et al. In press). Observations
of distribution around Tierra del Fuego and Chile during the 1996/97
census suggest that these regions hold a population at least as
large as that of mainland Argentina, giving a South American population
of at least 1,300,000 pairs. Studies by the Environmental Research
Unit indicate that the Falkland Islands population must be well
in excess of 100,000 pairs, giving a minimum world population of
around one and a half million breeding pairs.

Annual monitoring
of selected colonies (Bingham 1994b, Bingham 1995a, Bingham 1995b)
shows that the Magellanic Penguin population of the Falkland Islands
has declined to about half its 1980s level. These declines coincided
with observations of low breeding success up until 1993/94.

In addition to its
Penguin Monitoring Programme in the Falkland Islands, the Environmental
Research Unit now conducts similar studies at a number of Chilean
breeding sites along the Straits of Magellan. These studies suggest
that the Magellanic Penguin decline observed in the Falkland Islands
has not been evident in the Magellanic region of Chile, despite
its close proximity and similar breeding habitat to the Falkland
Islands.

One such site is
Isla Magdalena, which lies in the Straits of Magellan and covers
an area of less than 1 sq.km. The 1997/98 census conducted by the
Environmental Research Unit shows that this tiny island holds a
population of around 41,000 breeding pairs of Magellanic Penguin;
equivalent to about a third of the entire Falkland Islands population.
Comparison with a similar census conducted during 1940 suggests
little significant change over the last 60 years (CONAF).

The 1997/98 population
in the Straits of Magellan increased by an average of 17% since
1996/97. Chick survival rates were also high during 1997/98, with
the lowest rate observed in the Straits of Magellan (range 1.28
- 1.71 chicks fledged per nest) still being higher than the highest
rate observed in the Falkland Islands (range 0.79 - 1.23 chicks
fledged per nest).

Further evidence
of the differing fortunes of the two regions can be seen from the
breeding sites themselves. Magellanic Penguin colonies around the
Falkland Islands generally feature a very high percentage of unoccupied
burrows, with an average of more than 70% of burrows being unoccupied.
Similar breeding sites in the Straits of Magellan hold less than
half the proportion of unoccupied burrows (< 35%), suggesting lower
levels of adult mortality or higher levels of recruitment. There
is no commercial fishing activity around the Straits of Magellan.

South America is
also home to the Humboldt Penguin and the Galapagos Penguin, but
these species were outside the scope of this census. The Environmental
Research Unit has not conducted any research on either of these
species, but there are other organisations that have. The estimated
world population sizes of these species are less than 15,000 and
1,000 breeding pairs respectively. (Vargas 1996, Zavalaga 1997).